how do you make powdered milk or other dehydrated liquids?

Question

I dont understand how they do it and when added to water returs to a similar state. The same with cheese sauce mixes.

can anyone help me out?

Answer 1

There are two ways to do this.
1) Roller drying - this was the original method of drying milk. The liquid milk or WHY is fed onto steam heated rollers where it boils the water off. The more or less dry material is scraped off and finally dried on a belt in a heated tunnel. The problem with this method is that the milk is too thoroughly cooked and becomes much less soluble when it is dissolved up again 'reconstituted'. It also has a strong 'cooked' note.
2) Spray drying - here the liquid is pasteurised and heated before spraying into a tall heated tower where the droplets dry very rapidly with minimum cooking - denaturation. The powder so produced is only one or two percent insoluble and has very little 'cooked' flavour.
Many 'mixes' are not dried all together but mixtures of the ingredients. Cheese sauce may be e flavoured mix rather than contain any cheese - look on the packet for the ingredients listing.
RoyS

Answer 2

The process is called freeze drying. It is the same process as in making instant coffee.